1. Field of the Invention
The present invention relates to an image capturing technique that generates a composite image by coupling a plurality of images.
2. Description of the Related Art
There has been a method for generating a panoramic image by shooting a plurality of images, while changing an angle of a camera, and smoothly coupling right and left overlapping parts of each image to corresponding parts of other images using image processing.
There has also been a method for generating an image that has a wide dynamic range by shooting, while changing an exposure condition, a plurality of images including an image having little highlight-detail loss and an image having little shadow-detail loss, and composing them. The method is referred to as a high dynamic range (HDR) composition. Japanese Patent Laid-Open No. 2004-180308 discloses a technique for generating a panoramic image, in which one image having no highlight-detail loss and no shadow-detail loss is generated using the above-mentioned HDR composition, while an area is changed and shooting and composition are performed similarly so as to generate other images, and these HDR images are composed into the panoramic image.
However, since in the method disclosed in Japanese Patent Laid-Open No. 2004-180308, a plurality of images are shot in the same angle, it is thus necessary to fix the camera body on a tripod stand or the like when shooting a plurality of images, and to repeat shooting of a plurality of images and adjustment of a camera angle, requiring a complicated procedure.
Further, although an image that has a wide dynamic range is generated for each angle and brightness of each image is adjusted when it is coupled to another image, a difference in brightness level might remain at the border between the images coupled to each other since they are shot under different exposure conditions.